         new-col-val (apply f args-from-cols)
         new-column-hash (resolve-keys new-header new-col-val)]
     (merge row new-column-hash)))
-
-(defn- resolve-all-col-ids [dataset source-cols]
-  (map (partial resolve-column-id dataset) source-cols))
 
 (defn derive-column
   "Adds a new column to the end of the row which is derived from

        not-found-items (invalid-column-keys dataset cols)]
    (if (and (empty? not-found-items)
             (some identity cols))
      (let [inc-ds (inc/$ cols dataset)]
        (if (inc/dataset? inc-ds)
          (with-meta inc-ds original-meta)
          (with-meta (make-dataset [inc-ds] cols) original-meta)))
      (throw (IndexOutOfBoundsException. (str "The columns: "
                                              (str/join ", " not-found-items)
                                              " are not currently defined."))))))

                             (map first))]
    not-found-items))

(defn- resolve-all-col-ids [dataset source-cols]
  (map (partial resolve-column-id dataset) source-cols))

(defn- all-columns
  "Takes a dataset and a finite sequence of column identifiers.

